• DAY1SVR: Day 1 Convective

    From Mike Powell@618:250/10 to All on Mon Jun 15 07:30:06 2026
    ACUS01 KWNS 150528
    SWODY1
    SPC AC 150527

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1227 AM CDT Mon Jun 15 2026

    Valid 151200Z - 161200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
    AND EVENING ACROSS PARTS OF THE SOUTHERN HIGH PLAINS...

    ...SUMMARY...
    Strong thunderstorm activity may impact the higher terrain of
    northeastern New Mexico into adjacent high plains late this
    afternoon into evening, accompanied by at least some potential for
    severe hail and wind.

    ...Discussion...
    Higher latitude blocking appears likely to persist with little
    general change through this period. This regime will maintain a
    broad area of cyclonic flow with anomalously low heights, which may
    deepen further to the south of the central and eastern Canadian/U.S.
    border vicinity, as a significant short wave trough digs across the
    Dakotas through portions of the Upper Midwest by 12Z Tuesday.

    Models indicate that this is likely to be accompanied by a more
    notable southward surge of cooler/drier air, in the wake of a
    stalling, weakening preceding cold front reaching the southern
    Atlantic/Gulf Coast vicinity. With higher boundary-layer moisture
    content and stronger potential instability largely becoming confined
    to the south of the westerlies, the potential for organized severe
    thunderstorm development appears seasonably low today through tonight.

    ...Southern Rockies into adjacent Great Plains...

    Beneath a northwesterly mid-level regime, which may modestly
    strengthen to the southwest of the digging short wave trough by this
    late afternoon, models indicate that moistening on southerly
    low-level flow may contribute to modest destabilization across the eastern/southeastern slopes of the southern Sangre de Cristo
    Mountains into Raton Mesa vicinity. Perhaps aided by forcing for
    ascent accompanying a subtle digging short wave perturbation, it
    appears possible that thunderstorm activity, initiating with
    destabilization across the higher terrain, could consolidate into a
    small organizing cluster while propagating southeastward into the
    adjacent high plains. Forecast soundings across this region suggest
    that thermodynamic profiles may become potentially conducive to the
    development of large hail and strong to severe wind gusts into mid
    to late evening.

    ..Kerr/Weinman.. 06/15/2026

    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Tue Jun 16 07:42:48 2026
    ACUS01 KWNS 160551
    SWODY1
    SPC AC 160550

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1250 AM CDT Tue Jun 16 2026

    Valid 161200Z - 171200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TODAY THROUGH
    TONIGHT ACROSS PARTS OF THE NORTHERN GREAT PLAINS INTO MIDWEST AND
    NEAR THE GULF COAST...

    ...SUMMARY...
    Areas of mainly widely scattered strong thunderstorm development,
    accompanied by at least some risk for severe weather, are possible
    across parts of the northern Great Plains into Midwest and near the
    Gulf Coast vicinity today through tonight.

    ...Discussion...
    Higher latitude blocking appears likely to maintain a broad area of
    cyclonic mid-level flow with anomalously low heights to the lee of
    the northern Rockies through the northern and middle Atlantic
    Seaboard. Within this regime, models suggest that an initially
    vigorous short wave trough (now digging into the Upper Midwest) may
    maintain strength into and across the Lake Michigan vicinity, before
    undergoing considerable deformation while turning eastward and
    northeastward, to the southeast of a mid-level becoming centered
    near the northern Manitoba/northwestern Ontario border. After
    rounding the crest of mid-level ridging centered over the northern
    mid-latitude eastern Pacific, it appears that another significant
    short wave perturbation will dig through the broadly confluent
    regime to the southwest of the low, across the northern Rockies
    through northern Great Plains by late tonight.

    In lower latitudes, mid/upper ridging emanating from the subtropical
    Atlantic may maintain considerable influence across the Florida
    peninsula today, while weak troughing, perhaps with a developing
    mid-level cyclonic circulation, slowly pivots across the lower Texas
    and Mexican Gulf coast.

    In lower levels, seasonably high boundary-layer moisture content has
    generally been maintained across much of the Gulf coastal plain. It
    appears that strengthening southerly low-level flow may support more substantive moisture return to the southeast of deepening surface
    troughing across the northern into central Great Plains by late tonight.

    ...Midwest/Great Lakes...

    Weak convection accompanying forcing for ascent associated with the
    lead short wave trough appears likely to persist and perhaps
    increase across the Upper Midwest through Great Lakes and Ohio
    Valley during the day. Coinciding low-level cooling is likely to at
    least slow, if not inhibit, boundary layer warming in the wake of
    this activity. However, various model output suggests that
    associated low-level moistening, coupled with a period of insolation
    beneath a developing mid-level dry slot, may be sufficient to
    support a corridor of modest destabilization as the mid-level cold
    pool (including 500 mb temperatures around -18 to -20C) overspreads
    the southern Lake Michigan vicinity late this afternoon. This
    environment might become sufficient for a developing broken band of
    vigorous convection, perhaps including supercells, posing a risk for
    severe hail/wind and possibly a tornado or two, before weakening
    later this evening.

    ...Central Great Plains...

    Forcing for ascent to support convective development along the
    stalling cold front, trailing the short wave trough progressing into
    the Great Lakes/Ohio Valley, remains unclear. However, there
    appears a general consensus within model output that boundary-layer
    moistening may support CAPE on the order of 1000-2000 J/kg across
    parts of southern Kansas into southwestern Missouri, where mid-level
    inhibition may remain weak enough through late afternoon/early
    evening to allow for isolated/widely scattered thunderstorm
    initiation. If this occurs, guidance indicates sufficient shear for
    supercell development, before increasing inhibition suppresses
    convection later this evening.

    ...Gulf Coast...

    Models indicate modest strengthening of westerly flow (including
    20-40 kt in the 850-500 mb layer) in a belt across the north central
    through northeastern Gulf coast vicinity today. Coinciding with destabilization driven by daytime heating of the seasonably moist
    boundary layer, this may support modestly organizing convection,
    perhaps transient supercell structures, posing a risk for damaging
    wind gusts and perhaps an isolated tornado or two.

    ...Northern Great Plains into Midwest...

    Models suggest that a corridor of fairly deep boundary-layer mixing
    will precede the vigorous short wave trough digging across and
    east-southeast of the Canadian/northern U.S. Rockies. It appears
    that associated mid-level forcing for ascent will contribute to
    sufficient destabilization to support scattered thunderstorm
    development with potential to produce some hail and scattered strong
    to severe surface gusts late this afternoon into evening.

    Within strengthening downstream warm advection, forcing for ascent
    may begin to interact with better elevated moisture return to
    support increasing strong thunderstorm development with potential to
    producing severe hail by late tonight, across parts of eastern Iowa
    and adjacent portions of the Midwest.

    ..Kerr/Weinman.. 06/16/2026

    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Fri Jun 19 07:57:25 2026
    ACUS01 KWNS 191245
    SWODY1
    SPC AC 191244

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0744 AM CDT Fri Jun 19 2026

    Valid 191300Z - 201200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    TEXAS INTO THE SOUTHEAST...CENTRAL PLAINS...UPPER MIDWEST...AND
    SIERRA INTO THE NORTHERN GREAT BASIN...

    ...SUMMARY...
    Isolated strong to severe thunderstorms may produce gusty winds and
    hail today across parts of the the Upper Midwest and central Plains.
    Other strong thunderstorms may produce occasional damaging winds
    from north Texas/southern Oklahoma into portions of the Southeast,
    and separately across parts of the Sierra into the northern Great Basin.

    ...Texas into the Southeast/Carolinas...

    An expansive area of convection has developed this morning across
    north-central TX/southern OK, aided by modest low-level warm
    advection and a weak mid-level disturbance. Both low-level and
    deep-layer shear remain weak across this region (generally less than
    20-25 kt), which should tend to limit updraft organization and
    overall thunderstorm severity through the rest of the morning. But,
    a very moist airmass and substantial reservoir of instability are
    present ahead of this ongoing convection and south of a surface cold
    front extending across TX into the ArkLaTex and lower MS Valley.

    Current expectations are for an isolated severe/damaging wind threat
    to persist downstream into the afternoon across these areas as the
    moist airmass undergoes additional destabilization with daytime
    heating. Considered including higher wind probabilities, but
    confidence in a more organized/severe MCS remains low owing to the
    weak deep-layer shear. Additional thunderstorms have also formed
    south into central/south-central TX this morning. This activity may
    also pose some risk for severe winds with the stronger cores as it
    develops east-southeastward through the day, even though shear and
    overall updraft organization will remain modest.

    The Marginal Risk extending into the Southeast/eastern Carolinas has
    been generally adjusted southward to account for the position of the
    cold front, and expectations that the isolated damaging wind risk
    will likely remain confined along/south of this boundary. Stronger low/mid-level flow associated with the remnants of Arthur over the
    eastern Carolinas this morning is forecast to quickly shift offshore
    through the day. An isolated severe wind and brief tornado threat
    may exist along/ahead of ongoing precipitation across this region,
    although instability will remain limited.

    Scattered to numerous thunderstorms will likely develop this
    afternoon across parts of the FL Peninsula, with a preferential
    focus along the Atlantic Coast sea breeze given modest westerly flow
    aloft. While low/mid-level winds and related shear are expected to
    remain weak, the strongest cores could still become capable of
    producing occasional damaging winds as low-level lapse rates steepen
    with daytime heating.

    ...Upper Midwest...

    An upper low will remain over northern Manitoba/Ontario today, with
    a broad fetch of moderate northwest flow aloft across the northern Rockies/Plains. An embedded mid-level shortwave trough is forecast
    to move across the Dakotas and toward the upper MS Valley by this
    evening, with weak surface low pressure into northern MN. Strong
    surface heating along with generally 50s surface dewpoints and
    convergence near a cold front will lead to scattered storms across
    much of MN and western WI. Forecast soundings show cold profiles
    aloft over northern areas, though effective bulk shear will be
    somewhat weaker with northward extent. Deep-layer shear will be
    stronger over southern MN, but instability will not be as favorable
    farther south. Even so, cells that develop this afternoon and
    evening and track southeastward may be capable of producing severe
    hail given the cool mid-level temperatures. Occasional
    severe/damaging winds may also occur.

    ...Central Plains...

    Beneath modest northwest flow aloft, surface low pressure will
    develop over southeast CO today, with southeasterly low-level winds
    across the central Plains. This will aid modest low-level warm/moist
    advection, with 50s to perhaps low 60s surface dewpoints across KS,
    eastern CO, and southern NE. It remains uncertain if any
    thunderstorms will develop later today across this region, but the
    influence of the upper trough over the northern Plains may yield a
    few elevated cells. Additional warm/moist advection this
    evening/overnight may also support isolated convective development.
    Hail appears to be the primary risk, with moderate
    instability/deep-layer shear and somewhat steepened mid-level lapse
    rates potentially supporting supercells. However, confidence in
    sustained convection remains too low to include greater severe probabilities.

    ...Sierra/Northern Great Basin...

    As a weak mid-level shortwave trough advances inland from the
    eastern Pacific, isolated to scattered high-based thunderstorms
    should develop later today across parts of the northern Sierra
    Mountains into adjacent portions of the Great Basin. While low-level
    moisture will remain limited, a very deeply mixed boundary layer and
    some mid-level moisture/cooling aloft ahead of the shortwave trough
    should support weak instability and thunderstorm potential. This
    activity could become strong given some deep-layer shear, with
    isolated severe gusts/outflow possible.

    ..Gleason/Broyles.. 06/19/2026

    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)